Patent GB-688050-A (GB)
Title: Improvements in preselector mechanism for dispensing liquids
IPC: G01F15/06
Filed: 1950-05-19
Abstract: 688,050. Dispensing liquids. VEEDER-ROOT, Inc. May 19, 1950 [April 13, 1950], No. 12587/50. Class 116. In apparatus dispensing predetermined quantities of petrol the shutoff valve is opened by resetting the register to zero, the preselector being automatically set for maximum delivery and, on starting the motor, a clutch on the shaft of the preselector mechanism is disengaged to ptevent further manual operation of the mechanism until the quantity has been dispensed and the motor switched off. An electric motor 2, Fig. 8, drives a pump 3 causing liquid to flow through a meter 4 and hose 6. The meter is connected by a shaft 8 to a register 9 which has a reset shaft 10 and a drive shaft 11' and a slip clutch between the shafts 8 and 11. The preselector mechanism 20 is connected to the shafts 10 and 11 and rotates a shaft 16 connected to a switch 19 for the motor and to a valve 22, prior to the end of dispensing, to partially close valve 22 initially, and when the shaft is further actuated to close valve 22 completely and switch off the motor. The preselector and register must be reset to open the valve and switch. The preselector has a dial 36 secured to an indexing plate 37 which is fixed on a hub 39 on a shaft 40 journaled in the front and rear plates. The plate has notches 41 and a spring- urged pawl 42 to accurately position the dial. On the hub 39 is a ratchet wheel 45 which is rotated for resetting in either direction by a second ratchet wheel 46 fixed to a hub 47 loosely mounted on the shaft 40. The wheels are interconnected by a pin 48 on wheel 45 extending through a slot 49 in the wheel 46. A spring 50 extends between the pin 48 and wheel 46 so that the pin engages the end of the slot. When the wheel 46 is rotated clockwise, the wheels rotate simultaneously; if counterclockwise, there is lost motion until the pin has moved to the other end of the slot. The wheel 45 has teeth 51 with flat and inclined edges and is driven by a pawl 60. The wheel 46 has teeth faced in the opposite direction and, when the wheel is rotated counterclockwise, the teeth cam out the pawl. The dial is set by a knob 61 on the shaft 40 which has clutch mechanism 62 for engaging the shaft 40 with the hub 47. A spring 68 normally keeps the clutch disengaged. The clutch is operated by a bellcrank 23 connected to the motor switch so that when the motor is off the clutch is engaged, and when the motor is on the clutch is disengaged. The shaft 14 is coupled to a shaft 71 which has a crank 72 to reset the register. Pinned to the shaft 71 is a hub 73 with gear 74 which, through gears 75, 76, drives a gear 77 mounted on a sleeve 78 freely rotatable on the hub 47. The gear 77 carries a pawl 79 biased by springs 80 to engage the hub 47 which has a notch 81 by which the pawl 79 and gear 77 can drive the hub 47. Rotation of the hub 47 by gear 77 returns the dial to maximum setting. The reset shaft is automatically returned 45 degrees, the gear is also rotated, the pawl 79 being latched out by a latch 82 pivoted on the plate 31 with the nose biased towards the hub by a spring 83 limited by a pin 94. A flange 84 on the pawl 79 engages the nose of the latch 82 to cam it outwardly from the hub to disengage the notch 81. The latch will not interfere with the gear when rotated in a counterclockwise direction since the latch pivots and is cammed out of the way when engaged by the flange. The drive pawl 60 is pivotally mounted on a lever cam 90 pivoted on a shaft 91. The pawl is biased to engage the ratchet wheel 45 by a spring 92. The lever 90 has an internal eccentric cam 93 with depressions for a pair of pins on the flange 95 of the hub 96 mounted on a shaft 97. The arm 90 is biased upwardly by a spring 100 and is reciprocated each time one pin engages the flat portion of the cam 93. The hub 96 is secured by pins to a gear 98 which meshes with a gear 99 secured to the shaft 91. The shaft 91 is coupled to the shaft 15 and by the drive shaft to the register. During dispensing, the shaft 91 is rotated with the drive shaft and by gears 98, 99 rotates the pins reciprocating the arm 90 and pawl 60. The shaft 16 is coupled to a shaft 103 and has a trip pawl 104 biased by a spring 105. When the jack shaft 103 is released, the shaft is rotated by the pawl 104 to close the valve 22 and open switch 19. Secured to the shaft 103 and pawl 104 is a disc 106 with a notch 107 engaging a lever 108 pivoted on the shaft 97. A spring 109 biases the lever 108 into the engaging position. When the jack shaft 103 and disc 106 rotate counterclockwise, the lever 108 engages the notch 107 and holds the shaft 103 to permit dispensing. The lever 108 has a roller 110 engaging a cam 111 fixed on the hub 39 rotating with the dial 36. The cam 111 has projection 112 engaging roller 110 which pivots lever 108 to release disc 106. Projection 112 trips lever 108 when the dial has been returned close to zero. When the disc 106 is released by lever 108, shaft 103 and pawl 104 are free to rotate clockwise under the spring 105 until the end of the pawl 104 flanged at 104' engages against cam 115 loosely mounted on the shaft 97 rotated by gear 98. At release of lever 108, pawl 104 falls on part 115<SP>1</SP> so that the valve remains partially open and dispensing takes place at a greatly reduced rate. The cam 115 is driven by gear 98 by pin 116 on gear 98 which extends through slot 117 in carri 115. Cam 115 is in retard of gear 98 while the gear is driving the cam. When the flange 104' rides off one of the projections 115', the cam 115 can advance which permits the pawl 104 and shaft 103 to snap to the " off position. When the preselector is reset, the pawl 104 is cocked by a cam 120 on the shaft 71 which engages a roller 121 on the pawl 104 to latch it during reset. To reset the register independently of the preselector, the pawl 79 is omitted. A cam plate is rotatably mounted on the hub 47 with the gear 77 connected by a pin through an opening in the plate. The plate has two notches. One notch receives the pawl 60 which; during dispensing, operates the wheel 45. During reset, the gear and plate rotate together, the pawl is cammed outwardly, and will not affect the dial 36. The pawl engages a notch after reset. The other notch in the plate is engaged by a spring urged pin to hold the plate for dispensing. U.S.A. Specification 2,264,557 is referred to.